Non Linear Distortion and Dynamic Range Issues in the ... electronics for...in the Design Of Microwave Electronics for Communication and Remote Sensing Systems Alberto Santarelli

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Non Linear Distortion and Dynamic Range IssuesNon Linear Distortion and Dynamic Range Issues

in the Design Of Microwave Electronics for in the Design Of Microwave Electronics for

Communication and Remote Sensing SystemsCommunication and Remote Sensing Systems

Alberto Alberto SantarelliSantarelli

Short course on:

RF electronics for wireless communicationand remote sensing systems

Scuola di Dottorato in Scienze ed Ingegneria dell'InformazioneDottorato di Ricerca in Ingegneria Elettronica Informatica e delle Telecomunicazioni

13th, 14th and 20th July 2010, Facoltà di Ingegneria, Viale Risorgimento 2, Bologna

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A. Santarelli - Non linear distortion and dynamic range issues in the design of microwave electronics for communication and remote sensing systems – 14th July, 2010 2

SummarySummary

• Brief Overview of Wireless Systems

• Wireless T/R Front End Design Issues

• Non linear distortion, noise and dynamic-range issues in building blocks of wireless communication and remote sensing systems.

• Trade-off issues between nonlinear distortion, output power and power added efficiency in the design/optimization of microwave power amplifiers

• Basics of new generation electron devices for low-distortion, high-dynamic-range microwave circuit design.

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Wireless Systems Overview (I)Wireless Systems Overview (I)

Wireless Cellular Telephone Network (Typ. Freq. : 950, 1800, 2100 MHz)

• (2G) GSM (mod. GMSK) - EDGE (mod. GMSK/8-PSK)

• (3G) UMTS (mod. QPSK)

– e.g. W-CDMA provides HSPA up to 7Mbs

– Freq. Band 5MHz

• (3GPP) LTE (mod. QPSK, 16-QAM, 64-QAM)

– expected cell data rates of over 300 Mbps

– Freq. Band up to 20 MHz

• (4G) IP-based, Software Defined Radio (SDR), Cognitive Radio (CR)

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Wireless Cellular Telephone NetworkWireless Cellular Telephone Network

• Downlink (from BTS to Handset)

• Uplink (from Handset to BTS)

Base Terminal Station (BTS)

Different specs and

technologies used for uplink

and downlink…

e.g. 16-QAM - S/Nreq=11dB

Pout = 43 dBm

e.g. QPSK - S/Nreq = 5dBPout = 23 dBm

Fig. from Ref.[1]

DL

UL

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Wireless Systems Overview (II)Wireless Systems Overview (II)

Wireless Local/Personal Area Network (WLAN/WPAN)

WiFi• OFDM with subcarriers mod. PSK or QAM)

• based on the IEEE 802.11 standards

• Data rate up to 54 Mbit/s

• Freq.: 2.4 GHz, 5 GHz, Bandwidth up to 22 MHz

WiMax• based on the IEEE 802.16 standard

• Multi-user channel access techniques such as OFDMA

• Peak data rates of 144 Mbit/s in downlink and 35 Mbit/s in uplink (802.16e)

• Freq. 2.3–2.5 GHz and the 3.4–3.5 GHz, Bandwidths up to 20 MHz

MIMO channels available (multiple TX/RX antennas, spatial diversity)

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Wireless Systems Overview (III)Wireless Systems Overview (III)

Wireless Sensor Networks

• Spatially distributed autonomous sensors

• Equipped with a radio transceiveror other wireless communications devices

• Small dimensions, low-power consumption,low data rate, secure networking

• Typically based on theIEEE 802.15.4 standard (WPAN)

e.g. ZigBee in ISM radio bands and 2.4GHz

Super Node

Links to Other networks or

Similar Super Nodes

Motes

External Memory

Dig

ital I/O

port

s

Radio Transceiver

Analo

g I

/O P

ort

s

Microcontroller

A/D

D/A

Sensor

Sensor

External Memory

Dig

ital I/O

port

s

Radio Transceiver

Analo

g I

/O P

ort

s

Microcontroller

A/D

D/A

Microcontroller

A/D

D/A

Sensor

Sensor

Mote

Power Supply

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Wireless Systems Overview (IV)Wireless Systems Overview (IV)

Back-Haul – Terrestrial and Satellite Communications

• Point-to-Point Terrestrial or via-Satellite Microwave Radio Links(e.g. connecting Base Stations)

– dedicated high-capacitive terrestrial radio links at 38 GHz (mod. PSK/QAM)

• Point-to-Multipoint Microwave Access Technologies(broadband, fixed wireless, point-to-multipoint technology)

– WiMax

– Local Multipoint Distribution Service (LMDS) at 28-29 GHz (PSK/QAM)

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Wireless Systems Overview (V)Wireless Systems Overview (V)

Not only networks…

Satellite Remote Sensing and Communication

• Synthetic Aperture Radars

• Altimeters and radiometer applications

• Radioastronomy

• Satellite Radio Links for video, audio and data broadcasting (DVB-S/S2) and Internet Access at 12GHz (downlink) and 18 GHz (uplink)(mod. BPSK, 16APSK and 32APSK)

Frequency Bands: C – X – Ku and beyond…Reliability issues…

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Basic Building Blocks of RF FrontBasic Building Blocks of RF Front--EndsEnds

• Power Amplifier (PA) – provides signal power amplification just before the transmitting antenna

• Low Noise Amplifier (LNA) – provides amplification just after the receiving antenna by introducing minimal S/N degradation

• Mixer – provides up and down frequency conversion of signals

• Local Oscillator – provides sinusoidal waveform for carrier generation

• Frequency Synthesizer – Provides stable and programmable carrier generation and recovery

• Linear Filters and Phase Shifters– for band and channel selection, image rejection, IQ modulation, etc.

• Duplexer - allows using a single antenna for TX/RX

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DuplexingDuplexing

• Single antenna for RX and TX

• Time Division Duplexing (TDD) vs. Frequency Division Duplexing (FDD)

• RX has to be isolated from high power generated by HPA (otherwise: LNA desensitisation)

Half-duplex

Full-

duplex

Figs. from Ref. 2

FDD

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MixerMixer

( ) cosLO LO LO

v t V tω= ( ) cosS S S

v t V tω=

( ) ( )( ) cos cos2 2

out LO S LO S LO S LO S

A Av t V V t V V tω ω ω ω= + + −

The mixer ideally executes a perfect

multiplication of two input signals vA, vB

The Mixer provides Frequency Conversion

Up-conversion Down-conversion

( )LO

v t

( )S

v t ( )out

v t

( ) ( ) ( )out LO S

v t A v t v t= ⋅ ⋅

• Actual Mixers suffer from noise and distortion

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Example of a Microwave T/R FrontExample of a Microwave T/R Front--EndEnd

Fig. from Ref. 2

Lucent Tech. GSM Transceiver

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Typical Trends in T/R FrontTypical Trends in T/R Front--End ArchitecturesEnd Architectures

• ADC and DAC progressively shift towards the antenna(Software Defined Radio)

• Reconfigurable building blocks(“frequency-agile” RF components and systems)

� Digital RF circuits

� Analog RF circuitswith digital control(e.g. with use ofRF-MEMS)

• High-efficiencyPA schemes(Doherty Amplifiers,Class-S Amplifiers,Envelope Tracking,…)

Fig. from Ref. 1Linearity ??? PA Linearization techniques

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Limiting Factors of Nonlinear RF Building BlocksLimiting Factors of Nonlinear RF Building Blocks

• Broad-band and Parametric Noise

• Nonlinear Distortion

• Component Dynamics cannot be neglected at microwaves

• Power consumption (energetic efficiency, self-heating, reliability)

• Transmission of Wide-Band signals leads to critical requirements for the Receivers in

terms of robustness against strong Interfering Signals

• Flexibility and Reconfigurability

DYNAMICRANGE

Nonlinear RF building blocks of T/R Front Ends (PA, LNA, Mixer, Oscillator

and Frequency Syntethasizer) are basically limited in performance by

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Noise in Electrical ComponentsNoise in Electrical Components

• Broad-Band (Additive) Noise(e.g. Thermal, Diffusion/Shot-Noise)

– Due to fluctuations of carrier velocity

– Broad-Band White Power Spectral Density (PSD)

• Parametric (Modulating) Noise(e.g. 1/f Flicker Noise, G-R Noise)

– Due to fluctuations of carrier population

– Low Frequency-Generated (LFG) Noise

– “Colored” PSD

– Converted to RF by multiplicative mixing phenomena

Broad-Band

Noise

1/f Noise

PSD(f)

ffC

Corner Frequency

HBTs :1-100 KHz

FETs: 1-10 MHz

Two basic kind of noise exist in electrical components:

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Effects of Noise on T/R FrontEffects of Noise on T/R Front--End Performance End Performance

• Phase Noise of the locally generated oscillation: carrier generation with

inherent spurious “noisy” modulation

• Same problem both in the Transmitter and in the Receiver (Carrier

Recovery)

• No benefit from increasing signal power since phase noise side-band

amplitude also increases proportionally (non additive, but modulation noise)

Phase Noise

Broad-Band Noise

• Sensitivity (and dynamic range) reduction of the Low Noise Amplifier

• Noise Figure degradation due to strong adjacent interfering signals

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At microwave frequencies (presence of reactive phenomena) the Power Amplifier is nonlinear with memory

Linear With Memory:

Nonlinear with Memory:

Nonlinear Memory-less:

0( ) ( ) ( )

MT

y t h x t dτ τ τ= −∫

1 1 1 10

2 1 2 1 2 1 2

3 1 2 3 1 2 3 1 2 3

( ) ( ) ( )

( , ) ( ) ( )

( , , ) ( ) ( ) ( )

MT

y t h x t d

h x t x t d d

h x t x t x t d d d

τ τ τ

τ τ τ τ τ τ

τ τ τ τ τ τ τ τ τ

= − +

+ − − +

+ − − − +

+

∫

∫∫

∫∫∫K

2 3

2 3( ) [ ( )] ( ) ( ) ( )y t f x t x t x t x tα α α1= = + + +K

VOLTERRA SERIES

Distortion in Nonlinear Components (focus on PA)Distortion in Nonlinear Components (focus on PA)

PAx(t) y(t)

Which description for the PA ?

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A Simplified Description of A Simplified Description of PAsPAs

• Volterra kernels h1(τ1), h2(τ1, τ2), h3(τ1, τ2, τ3),… completely characterizethe amplifier nonlinear dynamic response

• Volterra series can be practically used only for weak non-linearity, since kernels measurement at microwave frequencies is difficult

• Modified Volterra Series descriptions exist. They are based on modified kernels and are more suited for practically dealing with weak and strong nonlinearities

However…

• For a simplified analysis of nonlinear distortion in power amplifiers a purely memory-less power amplifier is assumed in the following

Simplified Analysis

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Nonlinear Distortion Characterization Nonlinear Distortion Characterization

• Harmonic Distortion

• Gain compression

(Pout vs. Pin, Power Gain vs. Pin)

• Intermodulation Distortion

• AM/AM and AM/PM plots

(Complex Gain vs. Pin,

Describing Function Approach)

Nonlinear Distortionhas been traditionallycharacterized by means of:

More recently-introducedFoM for dealing specificallywith Wireless Systems:

• NPR (Noise Power Ratio)

• EVM (Error Vector Magnitude)

• ACPR/ACLR (Adjacent Channel

Power/Leackage Ratio

• …

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Harmonic Distortion (I) Harmonic Distortion (I)

SingleSingle--Tone Sinusoidal ExcitationTone Sinusoidal Excitation

0( ) cos( )x t X tω=

2 3


ω

ω

|X(ω)|

|Y(ω)|

ω0

ω02ω03ω0 ….

PA Memory-less Model:

Input PA Excitation:

PA Output: ( )0

1

( ) [ ( )] cosAC DC k

k

y t f x t X X k tω∞

−=

= = + ⋅∑

Spectral re-growth at Harmonic (angular) Frequencies: kω0t

SPECTRUM

ANALYZER

SIN.

GEN.PA

x(t) y(t)

Scalar Measurement

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Harmonic Distortion (II)Harmonic Distortion (II)

• Very simple

but scarcely meaningful

for microwave communications

• Out-of-band harmonics only

(output filtering possible)

• Results can be too optimistic

(selective output matching

networks = harmonic filtering)

• Non realistic input test signal

(constant amplitude carrier, no modulation, zero bandwidth)

Fig. from Ref. 3

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Harmonic Distortion (III)Harmonic Distortion (III)

Typical PlotsTypical PlotsPout versus Pin

Transducer Power Gain vs. Pin

1dB

• 1dB (3dB) Compression Point

Pout1dB

Pin1dB

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IntermodulationIntermodulation Distortion (I)Distortion (I)

TwoTwo--Tone Sinusoidal ExcitationTone Sinusoidal Excitation

1 2( ) cos( ) cos( )x t X t X tω ω= +

ω

PA Memory-less Model:

Input PA Excitation:

PA Output: ( ), 1 2

,

( ) [ ( )] cosAC DC m n

m n

y t f x t X X m t n tω ω−= = + ⋅ +∑

Spectral re-growth at Harmonic (angular) Frequencies: mω1t+nω2t

Scalar Measurement

SPECTRUM

ANALYZER

SIN.

GEN.

PA

x(t) y(t)

SIN.

GEN.

+

ω1

ω2

SMALL

TONE SPACING:

∆∆∆∆ω = ω2-ω1<< ω0

|X(ω)|

ω1 ω2

ω0

2 3


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1 1 2

3

3 1 2

( ) [cos( ) cos( )]

3[cos(( ) ) cos(( ) )]

4

out-of-band terms

in-band higher order (odd)

w t X t t

X t t

α ω ω

α ω ω ω ω

= ⋅ + +

+ ⋅ − ∆ + + ∆ +

+ +

+

In mild large-signal operation intermodulation distortion is mainly due to 3rd order non-linearity

3

3 3

1

6

d f

dxα =

IntermodulationIntermodulation Distortion (II)Distortion (II)

Fig. from Ref. 3

1 2 1

2 1 2

2

2

ω ω ω ω

ω ω ω ω

− = − ∆

− = + ∆

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1

3

3IMD [dBc]PC

I P= =

ω1 ω2

∆∆∆∆ω ∆∆∆∆ω ∆∆∆∆ω

P1

P3 3rd-order IMD product

(in-band: co-channel distortion)

|X(ω)|

ω

|Y(ω)|

P5 5th-order IMD product

(out-band: adjacent channel distortion)

Channel

Bandwidth

Excitation

Tones

ω

IntermodulationIntermodulation Distortion (III)Distortion (III)

Carrier to Interference Ratio (CIR)

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IntermodulationIntermodulation Distortion (IV)Distortion (IV)

• Co-channel and Adjacent Channel Distortion Evaluation

• Input test signal with non-zero bandwidth (amplitude and phase modulation)

• Quite simple measurement set-up

• Scalar Measurement

A closer look to the two-tone excitation…

ω0 = central carrier frequency

Ex(t) = complex modulation envelope

{ }0( ) Re ( )j t

xx t E t e

ω= ⋅

2 21 2( )

j t j t

xE t X e X e

ω ω∆ ∆−

= ⋅ + ⋅

EX(t) has variable amplitude and phase:

1 20 ( )x

E t X X≤ ≤ +

0 ( ) 2x

E t π≤ ∠ ≤

GOOD SIGNALFOR NONLINEAR TESTING

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OUTPUT

IP3

INPUT

IP3

1

3

High-linearity

amplifier:

3

1

-30 -40 dBcP

P= ÷

3 1 33

2

P POIP

⋅ −=

ThirdThird--Order Intercept Point (IP3)Order Intercept Point (IP3)

Alternative way of expressing the PA distortion specification

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Modulated input signal:

Output signal (neglecting out-of-band

harmonics, but including both co-channel

and adjacent channel interference):

Ex(t), Ey(t) are slowly time-varying when modulated signal bandwidth BW<<ω0

QUASI-STATIC AMPLIFIER DESCRIPTION

No memory on signal modulation envelopesbut PA complex response considered at ω0

G is a complex Describing Functiononly dependent on |Ex(t)| since PA is a

time-invariant non-linear system

{ }0( ) Re ( )j t

xx t E t e

ω= ⋅

{ }0( ) Re ( )j t

yy t E t e

ω= ⋅

0( ) , ( ) ( )

y x xE t G E t E tω= ⋅

Describing Function Model of Describing Function Model of PAsPAs

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can be measured (vector voltmeter)

or computed (HB) under amplitude-swept

sinusoidal excitation

• G [ω0,|Ex(t)|] completely describes the nonlinear amplifier response to any

signal x(t) with relatively small bandwidth BW<< ω 0

• SCALAR GAIN COMPRESSION (1dB) NOT SUFFICIENT !

� no AM/PM conversion;

y

x

EG

E=

J GG G e

∠= ⋅

AM/AM

conversion

AM/PM

conversion

|Ex|

|G|

G∠

|Ex|

Complex

Describing

Function

AM/AM AM/AM -- AM/PM PA Behavioral ModelAM/PM PA Behavioral Model

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Adjacent Channel Power Ratio (ACPR)Adjacent Channel Power Ratio (ACPR)

Quantifying PA performance in the final application

Adjacent ChannelPower Ratio (ACPR)

SPECTRUM

ANALYZER

(W)-CDMA

Modulated

Source

PA

x(t) y(t)

( )

( )

Bin

Bou

y

y

t

PDF f df

ACPRPDF f df

⋅

=⋅

∫

∫ Bout

Bin

Different definitions of Bin Bout

depending on the Ref. Std.

Fig. from Ref. 4

Fig. from Ref. 5

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Noise Power Ratio (NPR)Noise Power Ratio (NPR)

• Used initially for characterizing multi-carrier

power amplifiers

• A broad-band Additive Gaussian White Noise

(AGWN) source is used to simulate the

presence of many carriers of random amplitude

and phase

• Band-pass Filtering approximately equal to the

Channel Bandwidth

• Equivalent to: (C+I)/I

SPECTRUM

ANALYZER

AGWN

Source PAx(t) y(t)

Notch

FilterBand-

pass

Filter

Fig. from Ref. 6

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Error Vector Magnitude (EVM)Error Vector Magnitude (EVM)

Vector

Signal

Analyzer

Digitally

Modulated

Source

PA

x(t) y(t)

• PA Specifications often given in terms of peak and rms value of the EVM

Figs. from Ref. 7

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Specs. of various Wireless Systems (example)Specs. of various Wireless Systems (example)

Fig. from Ref. 8

ACPR

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Energetic EfficiencyEnergetic Efficiency

PAx(t) y(t)

RF

outPRF

inP

DC

inP

Power Added Efficiency

RF RF

out in

DC RF

in in

P PPAE

P P

−=

+

Energetic Efficiency

RF

out

DC RF

in in

P

P Pη =

+

In the presence of an modulated signal, efficiency becomes a function of the

instantaneous signal envelope amplitude

Average Energetic Efficiency

RF

out

DC RF

in in

P

P Pη =

+

where, for instance: ( )RF

out y y yP P E E dE= ⋅∫p(E) Probability Density Function of the Envelope Amplitude

Fig. from Ref. 8

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Thermal Aspects (PA SelfThermal Aspects (PA Self--Heating)Heating)

Power dissipated into the device:(time-dependent quantity due to the inst.

variations of the Env. Amplitude)

• High-Efficiency is needed for limiting the Internal Device Temperature

• Peak and Average Internal Device Temperature must be kept under tolerable

limits for reliability

• Proper design of the assembly structures for optimal heat extraction (package)

11DC RF RF RF

D in in out outP P P P P

η

= + − = ⋅ −

Internal Device Temperature:

(thought as spatially averaged

along the FET channel)Channel-to-Back-Side

Thermal Resistance

[W/°C]

B DT T R Pϑ= + ⋅

Wafer Back-Side

Temperature

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Linearity vs. Efficiency TradeLinearity vs. Efficiency Trade--offoff

• In many power amplifier (e.g. class-A/AB) the maximum efficiency is obtained

for peak output power corresponding to a maximum of tolerable distortion

• Whenever the instantaneous input signal envelope amplitude corresponds to

input power lower than PEP the efficiency dramatically drops

• Constraints on PA distortion often lead to choose: PEP << Pin1dB (BACK-OFF)

[dBm]PEP

RF Output Power

[dBm]

RF

inP

RF

outP

ˆ RF

outP

[dBm]

DC input Power

[W]

RF

inP

DC

inP

PEP

η Efficiency

[%]

[dBm]

RF

inP

η̂

PEP

(Peak Envelope Power – PEP) Figs. from Ref. 8

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Peak to Average Ratio (PAR)Peak to Average Ratio (PAR)

• High-spectral-efficiency modulation

schemes are characterized by large PARs

(or crest factor)

• The same happens when a large number of independently modulated sub-

carriers are added to form the signal to be transmitted (such as with OFDM)

• PA average energetic efficiency

may become extremely low

in the presence of large PARs

combined with power back-off

• Dedicated PA solutions needed

(e.g. Doherty Amplifier)

PAR (typ.) [dB]Mod. (examples)

12OFDM

10.6W-CDMA (DL carrier)

7.764-QAM

3.5-4QPSK

( )

( )

v peak

v rms

tPAR

t=

E

E

&

&

vE& Complex envelope

of the modulated signal

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Effects of Noise and Distortion in LNA and MixersEffects of Noise and Distortion in LNA and Mixers

Noise Floor(Broad-band noise)

Strongest Signal limited by:

Weakest signal detected limited by:

Nonlinear Distortion(e.g. P1dB, P3dB)

DYNAMIC

RANGE

[ ] 30 10log( )dB

Noise Floor Input dBm kTB NF= + +

Spurious Free Dynamic Range (SFDR)(upper power limit corresponds to 3°-order

Intermodulation Product equal to the Noise Floor)

DR IS CRITICAL IN WIDEBAND WIRELESS SYSTEMS DUE TO LINEARITY CONSTRAINTS AND STRONG INTERFERING ENVIRONMENT

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The Doherty Power Amplifier (I)The Doherty Power Amplifier (I)

• Two PAs combined

– Carrier PA (class-B)

– Peaking PA (class-C)

• Only Carrier PA is working forsmall input signal envelopeamplitude (e.g. Pin < α ⋅ PEPwith 0.25<α<0.5)

• Max. efficiency of the Carrier PA isachieved at Pin = α ⋅ PEP (ideally 78.5%)

• Both PAs contribute output power for Pin > α ⋅ PEP

• Equivalent load impedances vary with increasing envelope amplitude (ZLCarrier ↓, ZLPeaking ↑) implementing a sort of “active load-pulling” mechanism

• Both PAs deliver 50% of output power at PEP

Fig. from Ref. 8

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The Doherty Power Amplifier (II)The Doherty Power Amplifier (II)

• Average efficiencies nearly doubledat equal ACPR

• Lower α are chosen for high-PAR signals

• Limitations exist with UWB signals due tofreq. selective matching networks and transmission lines

S-Band TX50W – Si-LDMOS

IS-95 CDMA

Figs. from Ref. 8

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Other Efficiency Enhancement TechniquesOther Efficiency Enhancement Techniques

Limitations with UWB signals due to the limited

bandwidth of the Bias Modulator (DC/DC converter)

Envelope Elimination and Restoration (EER)

(Final PA stage operating

in class-C/D/E/F)

Techniques based on “Bias Modulation”

Envelope Tracking (ET)

(Final PA stage operating

in class-A/AB)

Figs. from Ref. 8

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PA Linearization TechniquesPA Linearization Techniques

• FeedBack

• FeedForward

• Predistortion

Three main families of PA Linearization Techniques:

Example: (DIGITAL) PREDISTORTION

Red: Unlin. PA

Blue: Linearized PA

Figs. from Ref. 8, 9

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• Conflicting requirements on output power, efficiency and high linearity

• Search for optimal values of source/load impedances, bias conditions, bias networks, non-linearity compensating structures, etc

• Device technology suitably chosen according to frequency, output power,…

• Source/Load-pull device characterization(IMD, output power, power-added-efficiency plots)

• Numerical simulation with suitable non-linear transistor models and CAD tools (Harmonic Balance, Transient Simulation, Envelope Simulation)

DESIGN TOOLS

PA DesignPA Design

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-1

-0.5

0

0.5

1

-1

-0.5

0

0.5

10

20

40

60

80

40

40

50

50

-1

-0.5

0

0.5

1

-1

-0.5

0

0.5

10

20

40

60

80

40

40

50

50

Output Power (1st Harmonic)

Source/Load Pull PA CharacterizationSource/Load Pull PA Characterization

Plots of main FoM versus input/output reflection coefficients (impedances)

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Nonlinear Transistor Models Nonlinear Transistor Models

Physics-based models: derived by physical principles applied to the

device structure

• Direct link between technological process parameters (materials,

geometry, doping profile,…) and electrical response

• More suitable for device design/analysis

Empirical Compact Models: measurements based

e.g. Equivalent Circuits use of lumped circuital elements to describe

measured characteristics

• Numerically efficient

• Widely used for MMIC and HMIC design

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IC Technologies for T/R FrontIC Technologies for T/R Front--EndsEnds

• Base-Band Processing:CMOS

• RF Front-Ends in Handset and Portable Devices (Pout < 1W):SiGe HBT (BiCMOS Integrated Circuits), CMOS, BJT

• RF Front-Ends in Base-Stations (Pout ~ 10-100 W):Si-LDMOS, GaN-HEMT

Wireless

Back-Haul, Satellite Links, SpaceRadio-Astronomy, Radars (GHz<f<THz)

• GaAs-PHEMT, GaN-HEMT, GaAs-HBT, InP-PHEMT

Transistors may be available for:

Mixed Analog/Digital Integrated Circuits, MMIC Design,

or in Package or Die for Hybrid Solutions

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PAsPAs for Handsets (Technology Overview for Handsets (Technology Overview -- Dec Dec ‘‘09)09)

Fig. from Ref. 10

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SiGeSiGe HeterojunctionHeterojunction Bipolar Transistor (HBT)Bipolar Transistor (HBT)

• Similar to well-known BJT, but the Base region is implemented by SiGe instead of Si by creating hetero-junctions (H-J).

• Due to the specific properties of H-J, electron injection efficiency is strongly improved even in the presence of a heavily doped Base

• Very small parasitic effects(and Base resistance) obtained alsothanks to the high Base doping

• Extremely good Transition Frequency (frequency at unity current gain with

short-circuited output)

• Integration with Standard CMOSprocesses (BiCMOS)

Fig. from Ref. 11

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BiCMOSBiCMOS (Si(Si--CMOS+SiGeCMOS+SiGe HBT) TechnologyHBT) Technology

Fig. from Ref. 12 (NEC)0.18-um RF SiGe BiCMOS

• Analog, RF and Digital Circuit Integrated into a single IC Process

• Most suited technology for the Software Defined Radio

• SiGe-HBT offers very low-noise (both 1/f and broad-band)

• Highly reliable

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High High PowerPower MOSFETsMOSFETs –– SiSi--LDMOSLDMOS

• Wide low-doped Drift Drain region for high Break-Down Voltage

• Wide channel widths (distributed structures)for High Drain Currents

• Output Power: tens/hundreds of Watt

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High Electron Mobility Transistors (HEMT)High Electron Mobility Transistors (HEMT)

• Hetero-Junction (H-J) between AlGaN and GaN layers

• N-Channel confined in a very shallow, almost bi-dimensional region into the intrinsic-GaN

• Extremely high mobility of carriers in the intrinsic GaN

• Devices obtained with high Break-down voltages (~100V), high power densities (5W/mm)

• SiC or Sapphire substrates

• Quite expensive but extremely promising technology Fig. from Ref. 13

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A A GaNGaN Foundry Example: Foundry Example: TriQuintTriQuint

Fig. from Ref. 14

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GaAs PHEMT GaAs HBT

GaAsGaAs--basedbased Technologies (Technologies (ExampleExample:UMS):UMS)

Fig. from Ref. 15

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GaAsGaAs--basedbased Technologies (Technologies (ExampleExample: UMS): UMS)

Fig. from Ref. 15

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Figure ReferencesFigure References

1. G. Fisher, “Next-Generation Base Station Radio Frequency Architecture”, Wiley Bell Labs Technical Journal, Vol12 , N. 2, Aug 2007

2. B. Razavi, “RF microelectronics “, Prentice Hall, 1997

3. P. Wambacq, W. Sansen, “Distortion Analysis of Analog Integrated Circuits”, Kluver Academic Press, 1998

4. Agilent AN 1307,” Testing CDMA Base Station Amplifiers”, Application Note, 2000

5. “Adjacent Channel Power Ratio (ACPR)”, Application Note, Anritsu, 20016. K. M. Gharaibeh, K. G. Gard, M. B. Steer, “The Applicability of Noise Power Ratio (NPR) in Real Communication

Signals”, ARFTG Conference, 2006 67th , vol., no., pp.251-253, 16-16 June 2006

7. Agilent PN 89400-14, “Using Error Vector Magnitude Measurements to Analyze and Troubleshoot Vector-Modulated Signals”, Product Note, 2000

8. F. H. Raab, P. Asbeck, S. Cripps, P. B. Kenington, Z. B. Popovic, N. Pothecary, J. F. Sevic and N. O. Sokal, “RF and Microwave Power Amplifier and Transmitter Technologies. Part I-II-III-IV”, High Frequency Electronics, Summit Technical Media, LLC, May 2003

9. W.-J. Kim, S. P. Stapleton, J. H. Kim, C. Edelman, “Digital Predistortion Linearizes Wireless Power Amplifiers”, IEEE Microwave Magazine, Sep 2005.

10. J. Choi, D. Kang, D. Kim, J. Park, B. Jin, and B. Kim, “Power Amplifiers and Transmitters for Next Generation Mobile Handsets”, Journ. Of Semiconductor Technology And Science, Vol.9, N.4, Dec 2009.

11. J.-S. Rieh , "A brief overview of modern high-speed SiGe HBTs," 8th Int- Conf. on Solid-State and Int. Circ. Tech., ICSICT '06, pp.170-173, Oct. 2006.

12. F. Sato, T. Hashimoto, H. Fujii, H. Yoshida, H. Suzuki, T. Yamazaki, “A 0.18-um RF SiGe BiCMOS Technology With Collector-Epi-Free Double-Poly Self-Aligned HBTs”, IEEE Trans. On Elect. Dev., Vol.50, N.3, Mar. 2003.

13. S. Zhong, T. Chen, C. Ren, G. Jiao, C. Chen, K. Shao, N. Yang, “AlGaN/GaN HEMT with over 110 W Output Power for X-Band”, Proc. of the 3rd European Micr. Int. Circ. Conf. (EuMIC’08), Oct 2008.

14. http://www.triquint.com

15. http://www.ums-gaas.com

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